The deal comes two days after the Bears said they couldn't reach an agreement with Urlacher, the eight-time Pro Bowl selection and the heart and face of the franchise. They also have an opening at strong side linebacker after Nick Roach signed with Oakland.

Williams gets a fresh start after missing time last season because of suspensions.

"This is a great opportunity for D.J. to restart his career after coming off suspension for part of the 2012 season," general manager Phil Emery said. "We see a player that has very good athletic upside who can contribute immediately at `Mike' (middle) linebacker. He is also a versatile player who has played both outside linebacker positions, giving us flexibility in the draft."

Williams has played both middle and outside linebacker. He missed nine games while serving a pair of NFL-mandated suspensions last season and was released by the Broncos on the eve of free agency, freeing up his $6 million salary.

The Broncos deemed the nine-year veteran expendable after Wesley Woodyard had a breakout season at weakside linebacker in Jack Del Rio's defense.

A first-round draft pick out of Miami in 2004, Williams played four different linebacker spots during his tenure with the Broncos and led the team in tackles five times. He is one of only five NFL players during the last nine seasons to post at least 800 tackles and 20 sacks, and he showed just how versatile he is by starting at a variety of positions while playing under a long procession of defensive coordinators and schemes.

But he turns 31 this summer and is coming off a difficult season, with the suspensions and a reduced role when he came back.

He had just 14 tackles in seven games and only made one start because of his suspensions, which cost him about $4 million in salary and relegated him to playing on special teams and in sub packages when he returned in November.

Williams was suspended six games for violating the league's policy on performance-enhancing drugs and three games for an alcohol-related arrest in 2010 that led to a conviction last August.

He was originally charged with driving under the influence, but a jury convicted him of the lesser charge of driving while impaired. He was also convicted of driving without headlights, the offense that prompted police to stop him near downtown Denver in the early morning hours on Nov. 12, 2010, before taking him to a detox facility.

In 2005, he pleaded guilty to impaired driving.

Williams also drew attention last summer when he posted on Twitter a picture of his new digital playbook and said he was being asked to switch positions again.

In Chicago, he gets a second chance with a team that's undergone some big changes.

The Bears fired coach Lovie Smith in the wake of a second straight late-season collapse that left them out of the playoffs despite finishing with 10 wins. They hired the offensive-minded Marc Trestman to get the most out of quarterback Jay Cutler and addressed some big holes by signing left tackle Jermon Bushrod from New Orleans and tight end Martellus Bennett from the New York Giants.

Scheme-wise, the Bears are not changing much from Smith's cover-2 on defense. But they made a huge change in parting with Urlacher, their longtime middle linebacker who was slowed by a knee problem and then missed the final four games with a hamstring injury.

The only starting linebacker returning is Pro Bowler Lance Briggs. Signing Williams gives management some more optionals in the draft. The Bears don't necessarily need to take a linebacker with the 20th pick, although they still have a hole to fill at the position.